Encryption and/or scrambling methods are commonly implemented in devices and systems to protect data from illicit access and/or tampering. For example, many providers of motion pictures experts group (MPEG) encoded multimedia content use encryption to prevent unauthorized copying of the MPEG content before it is decoded. However, to keep the encrypted data secure, the means of encryption and/or decryption also must be secure. One method used to ensure the “strength” of the encryption method is to use a proprietary encryption/decryption algorithm. However, the strength of this type of encryption depends on the secrecy of the proprietary encryption/decryption algorithm, which can rarely be assured. Other encryption methods utilize well-known encryption/decryption algorithms, but rely on the secrecy of a specific encryption key to ensure the “strength” of the encryption.
While ensuring the secrecy of a specific encryption key is generally much less difficult than ensuring the secrecy of a proprietary encryption/decryption algorithm, the private encryption keys used by conventional encryption systems are still relatively accessible by an unauthorized entity. In software encryption implementations, the private encryption key can often be obtained by accessing a location of the system memory of the system executing the encryption software. Alternatively, the traces or wires that connect different circuit elements of a system or device can be probed by a logic analyzer or other device to observe the encryption key and/or the decrypted data as it is transmitted from one circuit component to another. These methods of illicitly accessing the private key generally require minimal effort, thereby often defeating only casual attempts at accessing the private key.
Given these limitations, as discussed, it is apparent that a device to improve the security of encryption keys would be advantageous.